As with any measurement device, a calibration step must first be performed for a vibrating gyroscope. This is a step during which the corrections to be made to the unadjusted measurement value from the device are defined in order to improve its precision as a function of various additional measured parameters, such as the temperature, so that this measurement device operates accurately.
Conventionally, a vibrating gyroscope is calibrated before being used. It can be calibrated when it leaves the factory, for example.
In certain systems, a gyroscope is used by compensating for its bias and scale factor errors. In other systems, an internal calibration is applied to the gyroscope or gyroscopes used. Such internal calibration consists of determining correction coefficients within a control loop of the gyroscope concerned. For vibrating gyroscopes, such an internal calibration is based on a rotation of the position of vibration. The operating mode of the gyroscope allows measuring an absolute angle of rotation on the basis of a measurement of an angle representing the position of vibration of the gyroscope relative to measurement electrodes.
However, it is not possible to apply such a correction to a gyroscope used in gyrometer mode. In this mode, the position of vibration of the vibrating gyroscope is maintained in a fixed position, and the measurement is deduced from the control that must be applied to the gyroscope to maintain it in that fixed position of vibration. The values supplied by the physical measurement then no longer correspond to an angle but to a speed of rotation.